Byte Buddy is a code generation and manipulation library for Java

#1

Post by mooreds » Fri, Aug 08, 2025, 5:25 PM UTC

Byte Buddy is a code generation and manipulation library for Java
bytebuddy.net

Re: Byte Buddy is a code generation and manipulation library for Java

#2

Post by morkalork » Mon, Aug 11, 2025, 6:09 PM UTC

Reminds me of a side project I did when first starting CS! The Java byte code specification is absolutely approachable and if you've never looked at it before I recommend it (although this project says you can still use it without that knowledge)

Re: Byte Buddy is a code generation and manipulation library for Java

#3

Post by pjmlp » Mon, Aug 11, 2025, 6:17 PM UTC

Note that Java now has its own API for this purpose.

https://openjdk.org/jeps/484

Re: Byte Buddy is a code generation and manipulation library for Java

#4

Post by atomicnumber3 » Mon, Aug 11, 2025, 6:35 PM UTC

pjmlp wrote: post #3

Note that Java now has its own API for this purpose. https://openjdk.org/jeps/484

for those who might be clicking through thinking "since when??", the emphasis is on "now" - this was released in JDK 24.

bytebuddy predates it by at least a decade.

Re: Byte Buddy is a code generation and manipulation library for Java

#5

Post by brabel » Mon, Aug 11, 2025, 6:42 PM UTC

pjmlp wrote: post #3

Note that Java now has its own API for this purpose. https://openjdk.org/jeps/484

How does that compare in terms of usability and completeness?

Re: Byte Buddy is a code generation and manipulation library for Java

#6

Post by pjmlp » Mon, Aug 11, 2025, 7:09 PM UTC

atomicnumber3 wrote: post #4

pjmlp wrote: post #3

Note that Java now has its own API for this purpose. https://openjdk.org/jeps/484

for those who might be clicking through thinking "since when??", the emphasis is on "now" - this was released in JDK 24. bytebuddy predates it by at least a decade.

Hence the now on my comment. :)

Re: Byte Buddy is a code generation and manipulation library for Java

#7

Post by cogman10 » Mon, Aug 11, 2025, 7:12 PM UTC

brabel wrote: post #5

pjmlp wrote: post #3

Note that Java now has its own API for this purpose. https://openjdk.org/jeps/484

How does that compare in terms of usability and completeness?

It's complete but low level compared to Byte Buddy. A better comparison is the to ASM (which is what it was meant to replace).

https://asm.ow2.io/

Re: Byte Buddy is a code generation and manipulation library for Java

#8

Post by cogman10 » Mon, Aug 11, 2025, 7:14 PM UTC

If you are into code generation, another project of interest is Java Poet

https://github.com/square/javapoet

I've used it to do a mass refactoring of an annotation-based library. Worked pretty great.

Re: Byte Buddy is a code generation and manipulation library for Java

#9

Post by pjmlp » Mon, Aug 11, 2025, 7:14 PM UTC

brabel wrote: post #5

pjmlp wrote: post #3

Note that Java now has its own API for this purpose. https://openjdk.org/jeps/484

How does that compare in terms of usability and completeness?

I have not yet used it, only raising awareness.

This came to be, because Oracle noticed everyone, including themselves, were depending on ASM, so the JEP was born.

Re: Byte Buddy is a code generation and manipulation library for Java

#10

Post by cogman10 » Mon, Aug 11, 2025, 7:17 PM UTC

pjmlp wrote: post #9

brabel wrote: post #5

Earlier quoted context omitted.

How does that compare in terms of usability and completeness?

I have not yet used it, only raising awareness. This came to be, because Oracle noticed everyone, including themselves, were depending on ASM, so the JEP was born.

Yup, the ASM dependency is one that would constantly cause us headaches. A load of frameworks have a path to ASM for one reason or another and it requires an update every time you move up JVM runtimes.

It's usually not painful to update (just bump the version) but it's an annoyance.

In fact, Byte buddy has a dep on ASM.